1. Field of the Invention
The present invention relates to a beverage extracting apparatus for vending machines which mixes water and raw beverage material, filters or filtrates the mixture liquid via a filter and extracts the filtered mixture liquid.
2. Description of the Prior Art
A conventional beverage extracting apparatus for vending machines is shown in FIG. 10 (Japanese Utility Model Publication No. SHO 62-151681). A mixing chamber or ball 1 thereof mixes supplied water, for example hot water, and supplied raw beverage material, for example ground coffee. A mixture liquid 2 of the water and the raw material is introduced into a cylinder 3 through an outflow port 1a of mixing ball 1, a communication path 4 and an inflow port 3a of the cylinder, when a valve 5 opens. The valve is driven by a valve drive mechanism (not shown). After mixture liquid 2 is introduced into cylinder 3, valve 5 is closed and pressurized air is supplied into the cylinder via an air pipe 6. The mixture liquid 2 in cylinder 3 is forcibly filtered and extracted by the pressure of the supplied pressurized air via a filter 7 covering a bottom opening 3b of cylinder 3.
In such a conventional apparatus, the upper and lower end portions of communication path 4 extend vertically, and the portion between the upper and lower end portions extends at a slant. Therefore, the communication path 4 has flexed portions 4a and 4b on the upper and lower portions thereof, respectively. When mixture liquid 2 is introduced from mixing ball 1 into cylinder 3 through this communication path 4 as shown by arrows in FIG. 10, the mixture liquid impacts the inner surface of the communication path at the areas of flexed portions 4a and 4b. As a result, mixture liquid 2 cannot flow smoothly through communication path 4 and some of the raw material 8 (for example, coffee powder) of the mixture liquid sticks to the inner surface at the flexed portions. If this raw material 8 stuck to the inner surface of communication path 4 is not quickly removed, mold can form which makes for an unsanitary condition.
The mixture liquid flowing out of mixing ball 1 into communication path 4 flows generally in a swirling, whirlpool or vortex type of flow. However, this flow of the mixture liquid is interrupted at the areas of flexed portions 4a and 4b, and the water and the raw material are thus not uniformly mixed. Thus, in this conventional apparatus, pressurized air is supplied to cylinder 3 thereby stirring the mixture liquid in the cylinder, and thereafter, the mixture liquid is sent to a subsequent process in the vending machine. This stirring procedure in the cylinder 3 disadvantageously adds to the total-brewing time of the vending machine.
Further in the conventional apparatus shown in FIG. 10, since an upper inner surface 3c of cylinder 3 is formed as a horizontal flat surface and an upper surface 5a of valve 5 is formed as a trapezoidal surface including a horizontal flat top surface 5b, the mixture liquid from mixing ball 1 falls onto upper surface 5a of valve 5 and into cylinder 3 from the periphery of the upper surface of the valve. At that time, the falling mixture liquid impacts filter 7 or the mixture liquid already in cylinder 3, some of the mixture liquid thereby is scattered in the cylinder, and some of the scattered mixture liquid sticks to the inner surface of the cylinder above the liquid level 2a of the mixture liquid to be stored in the cylinder. This mixture liquid sticking to the inner surface of cylinder 3 and/or the mixture liquid remaining on the upper surface 5a of valve 5 is not filtered. If this remaining mixture liquid is not soon removed, it gets moldy and this is unsanitary.
Moreover, since the mixture liquid merely falls into cylinder 3 from the periphery of valve 5, the stirring action of the mixture liquid in the cylinder is not sufficient. Pressurized air supplied into cylinder 3 is needed to stir the mixture liquid in the cylinder, thereby extending the sale time of the vending machine.
Furthermore, in the conventional apparatus, since an air inlet port 3d connected to air pipe 6 is formed on the side wall of cylinder 3 at a position lower than liquid level 2a, the mixture liquid stored in the cylinder can flow towards the pressurized air supply means through the air pipe. To prevent this flow, a check valve (not shown) is provided on air pipe 6 or on another portion on the air supply path.
Moreover, in the conventional apparatus, since the pressurized air supplied from air inlet port 3d into cylinder 3 bubbles and the bubbles rise along the side wall of the cylinder as shown in FIG. 10, it is primarily only the mixture liquid adjacent the side wall on the side provided with the air inlet port which is stirred by the bubbles. Thus all of the mixture liquid in cylinder 3 cannot be sufficiently stirred. Also, when the bubbles of the pressurized air break or pop at the liquid level 2a near the side wall of cylinder 3, some of the mixture liquid is scattered by the breaking bubbles and the scattered mixture liquid sticks to the inner surface of the side wall. If this mixture liquid on the side wall remains for any length of time, it can also get moldy.